Speed change unit



March 15, 1955 3 Sheets-Sheet 1 Filed Oct. 15, 1952 FIGJ.

0. 2 0W 0 5 48 z 5 My 25 8 I 6 6 2 w 5 a 4 MW 1 4. 0 w -l o aw H IMUW ha 0 1 6 0 1 6 {a INVENTOR FRANK H. MUELLER W fim/fi W ATTORNEYS March 15, 1955 Filed Oct. 15, 1952 NIH F. H. MUELLER 3 Sheets-Sheet 2 INVENTOR FRANK l-l. MUELLER ATTORNEYS March 15, 1955 F. H. MUELLER 2,703,987

SPEED CHANGE UNIT Filed Oct. 15, 1952 3 Sheets-Sheet 3 FIG. 4. F165.

INVENTOR FRANK H. MUELLER M H s Q/r W ATTORNE Y3 United States Patent SPEED CHANGE UNIT Frank H. Mueller, Decatur, lll., assignor to Mueller Co., Decatur, 111., a corporation of Illinois This invention relates to power driven drilling machines of the type disclosed in U. S. Patents Nos.

1,956,129 and 2,470,044 and in pending applications 7 Serial Nos. 226,766 and 252,704, all to Mueller et al.

More particularly, this invention relates to a speed change I unit for drilling machines of this type.

Drilling machines of the type disclosed in the aforementioned patents and applications are used to cut openings in pipes, the size of such openings varying from 3 to 12 inches in diameter. Drilling machines, as heretofore constructed, have been provided with the highest gear reduction ratio necessary to effect 12 inch cuts with the power available, which usually is an air motor. In other words, more power is needed to make the larger cuts and, hence, a suitable gear reduction ratio for torque operation, or even for hand operation, must be built into the machine. In the machines of the type referred to above this gear reduction ratio has been 7 /3 to 1, so that in use of these machines it takes an air motor about eight minutes to advance the cutter one inch for most all sizes of cuts. It is evident that less power is requored to effect the smaller sizes of cuts and, hence, the air motor speeds up somewhat on the lesser loads, so that it takes about seven minutes to advance the cutter one inch in making a 6-inch cut and about /2 minutes to advance the cutter one inch in making a 3-inch cut.

When cutting a pipe for the purpose of inserting a pipe stopper, however, the cutter must travel completely through the pipe, so that even on the smaller size pipes, i. e. from 6 to 8 inches, a considerable period of time is taken to cut completely through the pipe. This time wastage on the smaller size pipes occurs because the available power, e. g. an air motor, cannot be utilized effectively to speed up the cutting rate because of the large fixed gear reduction ratio built into the machine;

Accordingly, when a large number of cuts have to be made in smaller size pipes there is a loss both of the operators time and of machine time. Such losses are uneconomical.

Therefore, it is an object of this invention to provide a speed change unit in the nature of an attachment for a drilling machine of the type under consideration which may be used to change the drive ratio from the motor to the cutter for most effective utilization of the motor power.

It is another object of this invention to provide a speed change unit of the type described which is simply and easily detachably secured to a drilling machine without structural modification of the latter.

It is another object of this invention to provide a speed change unit of the type described which will provide two separate drive ratios from the drive motor to the cutter.

It is another object of this invention to provide a speed change unit of the type described which, in conjunction with the gear ratio built into the drilling machine, will provide three separate drive ratios from the motor to the cutter.

It is another object of this invention to provide a speed change unit of the type described which is readily manipulable to change its drive ratio.

It is a further object of this invention to provide a speed change unit of the type described which is both simple in design and economical to manufacture.

Other objects and advantages of the invention will be evident from the following description and accompanying drawings, in which:

Figure 1 is a transverse sectional view of a drilling machine powered by an air motor and having a speed change unit embodying this invention attached thereto.

Figure 2 is a fragmentary View corresponding to Figure 1 and illustrating the unit shown in Figure 1 in reversed position for effecting a different drive ratio.

Figure 3 is an enlarged longitudinal sectional view of the speed change unit and mounting bracket illustrated in Figure 1.

Figure 4 is a front elevational view of the mounting bracket illustrated in Figure 1 Figure 5 is a side elevational view of the mounting bracket illustrated in Figure 4.

Figure 6 is a sectional view taken on line 6-6 of Figure 5.

Figure 7 is a fragmentary view of the lower end of the speed change unit shown in Figure 3.

Referring now to the drawings, there is illustrated in Figure l a conventional drilling machine 10 having an enclosed drive tube 12 concentrically enclosing a boring bar 14 and drivingly connected thereto by appropriate gears (not shown) at one end of the machine. The boring bar 14 projects from the other end of the machine 10 and is adapted to have a cutter (not shown) attached thereto. Advance of the. boring bar 14 is effected by means of a central feed screw 16 disposed within a hollow portion of the bar 14 and rotatedby the above-mentioned gears. Rotation of the drive tube 12 is eflFected by gears (not shown) enclosed within a gear housing 18 on the drilling machine 10 and driven by a projecting stub shaft 20 having a squared, or other appropriately shaped, noncircular outer end.

The drilling machine drive shaft 20 normally is adapted to be received within and rotated by the socketed shaft 22 of conventional air motor 24 which has the nose thereof disposed within a socket 26 in the arm 28 of a generally yoke-shaped conventional motor mount 30. The motor 24 is secured to the mount 30 by means of a thrust screw 32 threaded into the opposite end of the motor and bearing against the other arm 34 of the motor mount opposite the socket 26. The motor mount 30 is also provided, adjacent its socket 26, with a lateral lug 36 having a pair of spaced apertured ears 38 which are adapted normally to straddle an apertured lug 40 on the drilling machine and to be pivotally and detachably secured thereto by a pivot pin 42 that is fastened to the lug 40 by a wing set screw 44. A latch hook 46 pivoted on the motor mount 30 opposite the ears 38 is adapted to engage a latch pin 48 on the drilling machine 10 in order to firmly secure the motor mount 30, and the motor 24, in operating and driving position on the drilling machine. The construction thus far described is more or less conventional, so that a detailed description thereof is unnecessary.

In contrast to the above-described normal mounting of the motor 24 and the mount 30 on the drilling machine 10, there is shown in Figure 1 a speed change unit 50 embodying this invention interposed between the motor and the drilling machine This speed change unit 50 has a drive spindle 52 engaged within the socket of the motor shaft 22, which spindle is connected through internal reduction gears (later described) of the unit to the drive shaft 20 of the drilling machine 10.

As best shown in Figures 1, 3 and 7, the speed change unit 50 comprises a generally circular gear case 54 having a boss 56 on one side thereof provided with an arcuate outer surface. An elongated mounting bracket 58 has a lateral slot 60 complementary to the boss 56 and adapted to be received over the latter. A plurality of wing screws 61 (two as shown in the drawings) extend through the bracket 58 and into screw-threaded apertures in the boss 56 for detachably securing the speed change unit 50 to the bracket 58. The upper end of the bracket 58, as

viewed in Figures 1 and 2, has an enlargement 62 provided with an aperture 64 therethrough, which enlargement is adapted to be straddled by the motor mount ears 38 to pivotally and detachably secure the mount 30 to the bracket 58 by a pivot pin 66 which is fastened in place by a wing set screw 68. The lower end of the bracket 58 is provided with a pair of spaced apertured ears 70 adapted to straddle the lug 40 on the drilling machine 10 and to be pivotally and detachably secured thereto by the pivot pin 42. Thus, the bracket 58 detachably secures the speed change unit 50 to the drilling machine 10.

The upper end of the speed change unit 50 is provrded with a latch pin 74 located for engagement by the latch hook 46 on the motor mount 30, while the lower end of the speed change unit is provided with a latch hook 76 located for engagement with the latch pin 48 on the drilling machine so that the motor 24, the motor mount 30, and the speed change unit 50 may be rigidly secured in operating position on the drilling machine.

Referring now to Figure 3 of the drawings, the speed change unit comprises the essentially circular gear case 54 formed by a casing 78 having a cover 80 secured thereto, as by the screws 82, with an O-ring seal 84 therebetween to form an interior gear chamber 86. A ring gear 88 rotates in the chamber 86 and is provided with an axially projecting stub shaft 90 that is mounted in roller bearings 92 in a bearing housing 94 integrally formed with casing 78. A thrust washer 96 is interposed between the ring gear 88 and the opposed wall of the casing 78 while an interior circumferential groove 98 in the bearing housing 94 outwardly of the roller bearings 92 receives an O-ring 100 which bears against the periphery of the stub shaft 90 to provide an oil seal. The rim of the gear 88 bears against an annular thrust bearing surface 102 formed on the cover 80 within the chamber 86. The stub shaft 90 is provided with a socket 104 having a squared, or otherwise non-circularly shaped, outer portion 106 complementary to the drive shaft 20 for driving engagement therewith. The inner portion 108 of the socket 104 is circular and of substantially the same diameter as the diagonal of the squared portion 106. A latch block 110 is secured to the bearing housing 94 of the casing 78 by a screw 112 which also pivotally supports the latch hook 76.

The gear case cover 80 has a laterally oifset bearing housing 114 provided with interior roller bearings 116 which rotatably support the stub shaft 118 of a pinion gear 120 meshing with the ring gear 88. A thrust washer 122 is interposed between the pinion gear 120 and the opposed wall of the cover 80, while an O-ring 124, similar to the O-ring 100, disposed outwardly of the bearings 116 provides an oil seal for the shaft 118. The outer end of the pinion gear stub shaft 118 is threaded for the reception of an internally-threaded split clamp collar 126. A thrust washer 128 is interposed between the collar 126 and the opposed end of the bearing housing 114. The stub shaft 118 is provided with a socket 130 having an outer squared portion 132 and an inner circular portion 134 that are identical in dimensions with corresponding portions of the socket 104 in the ring gear stub shaft 90. A latch pin block 136 is secured to the bearing housing 114 by means of the latch pin 74.

Received within the socket 130 of the pinion gear stub shaft 118 is the drive spindle 52 having a circular portion 138 at the inner end thereof of slightly smaller diameter than the circular portions 108 and 134 of the sockets 104 and 130. The outer portion of the drive spindle has a squared section 140 complementary to the squared portions 106 and 132 of the sockets 104 and 130 of the gear shafts 90 and 118 and a squared section 142 complementary to and receivable in the socket in the motor shaft 22. Between these two sections 140 and 142 of the drive spindle 52 is an annular enlargement or collar 144. The circular portion 138 of the drive spindle 52 is provided with a spring-pressed ball detent 146 to retain the drive spindle in place in either socket 104 or 130. The outer ends of the gear shafts 90 and 118 are equidistant from a transverse plane passing centrally through the boss 56 so that the speed chan e unit 50 may be reversed, end to end, for drive in either direction therethrough, as later described.

The ring gear 88 is provided with 24 teeth 148, While the pinion gear 120 is provided with 12 teeth 150. so when the speed change unit 50 is attached to the drilling machine 10 in the position illustrated in Figure 1, the driving ratio through the unit is 2 to 1. For use with the unit the drilling machine preferably has a gear ratio of 3 to 1 built therein, i. e. three revolutions of the drilling machine drive shaft 20 efiect one revolution of the cutter. Therefore, when the unit 50 is attached to the machine 10, as shown in Figure 1, the overall gear ratio from the motor shaft 22 through the speed change unit and drilling machine to the cutter, or boring bar 14, is 6 to 1. This gear ratio is suitable for effecting the larger size cuts. for example, over eight inches. For cuts intermediate in size, as for example six to eight inches, the speed change unit 50 and bracket 58 are removed completely from the drilling machine 10, and the motor 24 and its mount 30 connected conventionally directly to the drilling machine, as heretofore described.

For the smaller size cuts, however, the position of the speed change unit 50 is reversed end to end and attached to the machine 10, as illustrated in Figure 2. In this position, the drive spindle 52 is withdrawn from the socket 130 in the pinion gear shaft 118 and placed in the socket 104 of the ring gear shaft 90, so that the motor shaft 22 is directly connected to the ring gear 88, and the drive shaft 20 of the drilling machine 10 is received within the socket 130 of the pinion gear shaft 118. In this position of the unit the overall drive ratio from the motor shaft 22 to the cutter, when the drilling machine has the aforementioned 3 to 1 gear ratio built therein, is 1V2 to 1, i. e. 1% revolutions of the motor shaft 22 for one revolution of the cutter. In this manner, the speed of the cutter may be increased with consequent reduction in time necessary to effect cuts in smaller size pipes.

it will be noted that the axis of the pinion gear is offset laterally from that of the ring gear 88. Hence, when the speed change unit 50 is reversed from the position shown in Figure 1 to the position shown in Figure 2, the bracket 58 must be provided with connecting means which accommodate the change in the relative positions of the parts. Accordingly, the upper end of the bracket 58 is provided with another aperture 152 which is offset laterally from the aperture 64. This aperture 152 receives the pivot pin in order to secure the motor mount 30 in proper position to receive the drive spindle 52. Similarly, the lower end of the bracket 58 is provided with another aperture 154 offset in the opposite lateral direction from the offset of the aperture 152 at the upper end of the bracket. This aperture 154 receives the pivot pin 42 in order to properly position the socket of the pinion gear stub shaft 118 to receive the drilling machine drive shaft 20.

In this same connection it also will be noted that the latch hook 76, the latch block 110 and its securing screw 112 are interchan eable with the latch pin 74 and the latch pin block 136. so that when the position of the speed change unit 50 is reversed from that shown in Figure l to that shown in Figure 2, the aforementioned parts are interchanged in order to securely fasten the ntrlotor to the mount and the latter to the drilling mac me.

It will thus be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the specific embodiment of the invention shown and described for illustrating the principles thereof is susceptible of change without departure from such principles. Therefore, this invention embraces all modifications which are encompassed by the spirit and scope of the following claims.

I claim:

1. A speed change unit for a power driven machine having a drive shaft for detachable direct connection to a motor and having means for detachably supporting the latter on the machine, said unit comprising: a gear case; reduction gears therein; rotatable means at opposite sides of said case for drive through said gears, each of said means being alternatively detachably connectable to the machine drive shaft and to the motor; and a supporting bracket having said case reversibly secured thereto, one end of said bracket having means thereon detachably connectable to the motor supporting means on the machine and the other end having means thereon for detachably supporting the motor.

2. A speed change unit for a power driven machine having a drive shaft for driving reception in the socketed shaft of a motor and having means for detachablv supporting the latter on the machine, said unit comprising: a gear case; reduction gears therein: rotatable socketed connecting means at opposite sides of said case for drive through said gears, each of said means being alternatively detachably connectable to the machine drive shaft and driven connection with the motor; a drive spindle having one end thereof alternatively drivingly receivable in said socketed connecting means and the other end thereof drivingly receivable in the motor shaft socket; and a supporting bracket having said case reversibly secured thereto, one end of said bracket having means thereon detachably connectable to the motor supporting means and the other end having means thereon for dctachably supporting the motor.

3. A speed change unit for a power driven drilling machine having a drive shaft for detachable direct connection to a motor and having means for detachably supporting a motor mount on the machine, said unit comprising: a gear case; reduction gears therein; rotatable connecting means at the opposite sides of said case for drive through said gears, each of said means being alternatively detachably connectable to the machine drive shaft and to the motor; and a supporting bracket having said case reversibly secured thereto, one end of said bracket having means thereon detachably connectable to the motor supporting means on the machine and the other end having means thereon for detachably supporting the motor mount.

4. The structure defined in claim 3 in which the machine means for supporting the motor mount includes means for pivotally supporting the motor mount and wherein the said one bracket end means is pivotally connectable to the machine means and the said other end means includes means for pivotally supporting the motor mount.

5. The structure defined in claim 4 in which the machine includes a pin engageable by a latch hook on the motor mount, and including a latch pin and a latch hook interchangeably mounted on opposite sides of the gear case, said gear case pin being engageable by the motor mount hook and said gear case hook being engageable with the machine pin.

6. In a speed change unit of the type described, the combination comprising: a gear case; a ring gear therein, the rim of said gear having thrust bearing engagement with one wall of said case; a stub shaft projecting from said gear and journalled in an opposite wall of said case; a pinion gear within said case meshing with said ring gear and having thrust bearing engagement with said one case Wall; a second stub shaft projecting from said pinion gear, journalled in said one wall, and extending out of said case; and a thrust collar on the outer end of said second stub shaft.

7. The structure defined in claim 1 in which the rotatable means are out of alignment and the means on both ends of the bracket include means for compensating for the misalignment of said rotatable means when the gear case is reversed on said bracket.

References Cited in the file of this patent UNITED STATES PATENTS Gustafson May 14, 1929 

